This invention relates generally to connectors for air ducts and housings, and more particularly to connectors used to connect housings and ducts having inlets and outlets of different shapes and/or sizes.
Air ducts used in homes and buildings are commonly used to transport air from a fan or blower to another location (e.g., a roof exhaust outlet, exterior exhaust vents, and the like). Similarly, air ducts can also be connected to inlets of a fan or blower housing. Unfortunately however, the shape of ducts and the shape of housings to which the ducts are connected are not the same. For example, the exhaust outlet of many existing fan or blower housings are often rectangular, while the cross-sectional shape of many types of commonly-used ducts is round. Similar problems can arise in trying to connect ducts together that have different sizes or shapes and in trying to connect housings having different inlet and outlet shapes.
As is well-known to those skilled in the art, duct connectors exist for connecting housings to ducts, ducts to ducts, and housings to housings when such elements being connected have inlets and outlets that do not match in size, shape, or size and shape. These duct connectors are tubular passages through which fluid flows as it is forced from housing to duct, duct to duct, or housing to housing by a fan, blower, or other air moving device.
As developments in air flow technology continue to be made, the importance of noise, power consumption, and cost in all aspects of air handling systems has increased significantly. For example, differences in noise levels of fan or blower assemblies and their connected ducts can mean the difference between acceptable and unacceptable assemblies and systems. As another example, the need to efficiently move air with minimal turbulence has been driven at least in part by the desire to low fan or blower speeds or to employ smaller fans or blowers in the same systems. Both results can save energy and lower noise in air handling systems.
Despite the needs for more efficient air handling systems and the advancements made in other areas of air handling systems, existing duct connectors remain a large cause of turbulence, fan or blower inefficiency, and noise. A significant cause of these problems is related to the shape of such duct connectors. An example of a conventional duct connector is illustrated in FIGS. 1-10. The duct connector (indicated generally at 10) is employed to connect a rectangular outlet of a housing or duct with a round inlet of a housing or duct, and is shown by way of example only.
To produce the transition between a rectangular inlet and an round outlet, the duct connector has a transitional passage which is shaped to join a rectangular end 6 of the duct connector with a round end 8. As is typical with conventional duct connectors, the duct connector 10 illustrated in FIGS. 1-10 establishes this connection by employing a transitional section 22 having multiple walls which define a number of steps, angled and multi-faceted surfaces, and sharp corners and breaks. Such features are often even more pronounced when the cross-sectional area of the duct connector inlet is different in size than the cross-sectional area of the outlet (as it is in the case of the duct connector 10 illustrated in FIGS. 1-10).
The steps, angled and multi-faceted surfaces, and sharp corners and breaks found in the transitional section 22 of the duct connector 10 significantly affects fluid flow through the duct connector 10. In particular, these features create turbulence, which creates noise and lowers the efficiency of the fan, blower, or other air moving device used to generate air flow through the duct connector 10. As a result, the air moving device must either be run at higher speeds or must be selected to be stronger in order to perform properly. Both of these options result in noise and inefficiency.
In light of the problems and limitations of the prior art described above, a need exists for a duct connector which lowers turbulence, improves air flow, enables the use of smaller air moving devices or the operation of air moving devices at lower speeds, and reduces noise. Each preferred embodiment of the present invention achieves one or more of these results.
The duct connector of the present invention preferably provides an improved transition of air flow between duct connector inlet and outlet shapes that differ in size and/or shape. The duct connector can be used to connect an inlet or outlet of a housing to a duct, can be used to connect ducts together, and can be used to connect housings together. By way of example, the duct connector of the present invention can be used to connect an exhaust outlet of a fan or blower housing to a duct having a different cross-sectional shape and size.
In some preferred embodiments, the duct connector has a rectangular inlet or passage at one end and a round outlet or passage at another end to connect a housing having a rectangular exhaust port to a duct having a round cross-sectional shape. Preferably, the duct connector has an intermediate passage that is located between the rectangular inlet or passage and the round outlet or passage. The intermediate passage preferably provides a smooth transition that is substantially free from steps and sharp corners between the rectangular passage to the round passage. In some embodiments, the intermediate passage includes opposing end walls and opposing side walls. These walls are joined together with transitional surfaces running along at least part of the intermediate passage. Preferably, each transitional surface provides a single smooth continuously curved surface between each side wall and adjacent end walls along the intermediate passage.
The smooth transition of the intermediate passage between the rectangular inlet or passage and the round inlet or passage helps to reduce turbulence within the duct connector. The smooth curved transitional surfaces interconnecting the side walls and end walls (described above) along the intermediate passage also helps to reduce turbulence within the duct connector. By employing these smooth transitions, the duct connector of the present invention can maintain or exceed air flow rates comparable to existing duct connectors while reducing the speed at which the connected fan, blower, or other air moving device operates. The smooth transitions therefore permit the motor driving the air moving device to be tuned down to run more efficiently and to reduce noise generated by the air moving device and noise related to air flow through the duct connector.
Duct connectors are commonly classified by a rated performance in terms of volumetric air flow through the connector. Some preferred embodiments of the duct connector according to the present invention achieve a similar rated performance of air flow as existing connectors while permitting the speed of the motor driving the fan, blower, or other air moving device to be reduced. The duct connector can also reduce the amount of noise generated by the motor and related to air flow through the duct connector.
More information and a better understanding of the present invention can be achieved by reference to the following drawings and detailed description.